Blab

(PW) talk too much

She is always blabbing about her supervisor’s personal life to her friends.

(freedictionary)

blab

v. blabbed, blab·bing, blabs

v.tr.

To reveal (secret matters) especially through indiscreet or unreserved talk.

v.intr.

1. To reveal secret matters.

2. To chatter thoughtlessly or indiscreetly. See Synonyms at gossip.

n.

1. An incessant or indiscreet talker.

2. Lengthy chatter.